1. Field of the Invention
One or more aspects of the present invention relate to methods of preparing silica aerogel powders, and more particularly, to methods of preparing silica aerogel powders having a short preparation time and of preventing heat and explosive reactions from being generated.
2. Description of the Related Art
Silica gel represented by SiO2.nH2O has SiO2 particles in which fine pores are connected to each other to constitute a rigid net structure. Each SiO2 particle is an amorphous particle that has high porosity of 90% or more and a specific surface area of 600 m2/g or more and is formed by solidifying a solvent such as water between SiO2 particles. Since silica gel has a wide surface area, silica gel has very high absorption with respect to alcohol or water, and thus silica gel may be used as a dehumidifier. Also, silica gel may be used as a heat insulating material, a catalyst carrier, an insulating material or the like. Likewise, even though silica gel is widely used in various fields, silica gel is very restrictively used. This is because there are a number of dangers related to preparation processes, and the preparation processes are complicated, thus increasing preparation costs.
Silica aerogel powders have been prepared by using a supercritical fluid extraction technique or an ambient pressure drying method. When silica aerogel powders are prepared by using a supercritical fluid extraction technique, preparation costs are increased, and there are dangers involved since much heat may be generated due to explosive reactions between materials (e.g., organosilane and inorganic acids). When silica aerogel powders are prepared by using an ambient pressure drying method, although the dangers related to the supercritical fluid extraction technique are removed, preparation costs may be increased by as much as the cost of removing the dangers, and a period of time taken for the preparation processes may be increased compared to the supercritical fluid extraction technique.